Flame spraying

ABSTRACT

THIS INVENTION RELATES TO AN IMPROVED FLAME SPRAY POWDER. THIS IMPROVED FLAME SPRAY POWDER HAS AT LEAS T 30% BY WEIGHT OF ITS PARTICLES OF A PARTICLE SIZE FINER THAN 50 MESH AND COARSER THAN 275 MESH.

United States Patent 3,743,533 FLAME SPRAYING George Yurasko, Jr., 4040 172nd St., Flushing, N.Y. 11358 No Drawing. Filed Oct. 28, 1971, Ser. 193,594 Int. Cl. B44d 1/08 US. Cl. 117-105.2 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to an improved flame spray powder. This improved flame spray powder has at least 3.0% by weight of its particles of a particle size finer than 50 mesh and coarser than 275 mesh.

It is known that, in the welding deposition processes known as flame spraying and particularly those two step flame spraying processes requiring a fusion operation after a metal is deposited by spraying, the deposits suffer from porosity and display a good amount of contamination. Further, the two step flame spray applications suffer from relatively low deposit efliciency e.g. deposited metal versus sprayed metal.

It is the general object of the present invention to avoid and overcome with deficiencies of the prior art practices by providing a flame spray powder that, on flame spray applications, produces denser and cleaner weld deposits.

Another object of the present invention is to provide a flame spray powder that will permit improved deposit efliciency.

The foregoing objects of this invention and other objects that will become apparent as the description proceeds are achieved by providing a powder for flame spraying that comprises particles of at least 30% by weight coarser than 275 mesh but finer than 50 mesh.

The weld deposits of flame spray applications have been known to suffer from a certain amount of expected porosity. This porosity diminishes the utility of flame spray applications which applications are well known in the art such as for example the gravity feed type described in copending patent application Ser. No. 702,035 filed on Jan. 31, 1968 now US. Pat. No. 3,620,454. Further, the two step flame spray processes suifer from relatively low deposit efliciencies.

A series of experiments were conducted to achieve a flame spray powder with improved weld deposits and higher deposit efliciency. After extensive experimentation it was found that powders containing at least 50 percent by weight, of particles coarser than 275 mesh but finer than 50 mesh, provided the desired improved results. These improved results are to be achieved by the fact that the powders of the present invention are of an overall coarser size than presently known flame spray powders. These coarser powders when traversing the flame area (of the flame spray torch) achieve a plasticized state which is optimum for compact deposition, with more powder being delivered and retained in the weld deposit.

Several examples of the flame spray powder of this invention are:

At least 30% by weight of powder finer than 50 mesh but coarser than 275 mesh.

At least 50% by weight of powder finer than 50 mesh but coarser than 275 mesh. 7

At least 60% by weight of powder finer than 50 mesh but coarser than 275 mesh.

3,743,533 Patented July 3, 1973 Ice Element: Percent by weight Carbon 1 to 5 Nickel 0 to 60 Silicon 0 to 5 Manganese 0 to 3 Boron 0.5 to 4 Iron Balance Nickel base alloys such as:

Element: Percent by weight Chromium 0 to 30 Silicon 0.5 to 6 Boron 0.5 to 5 Iron 0 to 6 Carbon .01 to 1.5 Nickel Balance Cobalt base alloys such as:

Element: Percent by weight Nickel 0 to 15 Chromium 0 to 4 Silicon 0.1 to 4 Boron .02 to 1.5 Phosphorous 0 to 1.5 Tin 0 to 25 Iron .01 to 2 Cobalt Balance It will be understood by those skilled in the art that the above defined alloys are recited merely as examples and that the novel features of the invention are applicable to all metal powers known in the art as metal spray powders.

It must therefore be understood that the objects of the present invention have been achieved by providing a flame spray powder capable of producing improved weld deposits with greater deposit efliciency.

What is claimed is:

1. A process for providing a substrate with a nonporous metallic coating comprising in sequence the steps of:

(I) flame spraying a particulate material consisting essentially of a metal powder comprising at least 30% by weight of particles finer than 50 mesh and coarser than 275 mesh and (II) fusing the metal which has been deposited on the substrate;

wherein a substrate is provided with a coating of reduced porosity, decreased contamination and with a greater percentage of deposited metal based on the metal sprayed.

2. The process of claim 1 wherein at least by weight of said particles are finer than 50 mesh and coarser than 275 mesh.

3. The process of claim 1 wherein the flame spray powder comprises an iron base alloy.

4. The process of claim 3 wherein the iron base alloy has the following composition:

Element: Percent by weight Carbon 1 to 5 Nickel to 60 Silicon 0 to Manganese O to 3 Boron 0.5 to 4 Iron Balance 5. A process for providing a substrate with a nonporous coating comprising in sequence the steps of:

(I) flame spraying a particulate material consisting essentially of a metal powder comprising at least 30% by weight of particles finer than 50 mesh wherein the metal powder is that of an alloy having the following composition:

Element: Percent by weight Chromium O to 30 Silicon 0.5 to 6 Boron 0.5 to 5 Iron 0 to 6 Carbon .01 to 1.5 Nickel Balance (II) fusing the metal which has been deposited on the substrate;

wherein a substrate is provided with a coating of reduced porosity, decreased contamination and with a greater percentage of deposited metal based on the metal sprayed. 6. A process for providing a substrate with a nonporous coating comprising in sequence the steps of:

(I) flame spraying a particulate material consisting essentially of a metal powder comprising at least 30% by weight of particles finer than 50 mesh wherein the metal powder is that of an alloy having the following composition:

wherein a substrate is provided with a coating of reduced porosity, decreased contamination and with a greater percentage of deposited metal based on the metal sprayed.

References Cited UNITED STATES PATENTS 3,625,732 12/1971 Nelson l1793.1 PF 3,617,358 11/1971 Dittrich 11793.1 PF

OTHER REFERENCES Flame Spray Handbook, vol. IH, Plasma Flame Process, by Ingham and Shepard, published by Metco Inc., Westbury, N.Y., copyright 1965, p. 134 relied on.

EDWARD G. WHITBY, Primary Examiner US. Cl. X.R.

11793.1 PF, 105,160R 

